**4. Antimicrobial potentials of beneficial microbes against antibiotic resistant strains**

The antimicrobial activities of beneficial microorganisms particularly lactic acid bacteria isolated from various sources against pathogens have been reported by many authors [7, 36]. Afolayan et al. [37] isolated lactic acid bacteria from different variety of "*Ogi*" a fermented cereal in western part of Nigeria with antimicrobial activities against various gastrointestinal pathogens. *Shigella* spp. are enteric pathogens which cause dysentery and diarrhea and are a leading cause of gastroenteritis- associated deaths in about 3–5 million under 5 years old children in developing countries [38, 39]. Lactic acid bacteria strongly inhibited gastrointestinal *E. coli* in co culture [40]. Cell free supernatant of *Lactobacillus casei* isolated from traditional yoghurt and milk was reported to strongly inhibit multi-drug resistant *Shigella sonnei* and *S. flexneri* [39], and also starter cultures in Nigerian yoghurt and the yoghurt itself has been reported to have strong inhibitory effects on gastrointestinal pathogens [41]. Salmonellosis contributes significantly to global morbidity and mortality. There are about 93.4 million cases of salmonellosis worldwide resulting in 155,000 death annually [42], *Lactobacillus* spp. with antimicrobial activity against *Salmonella typhi* were isolated by Abdel-Daim et al*.* [43] and *in vivo* anti-salmonella activities of lactobacilli has also been reported by Casey et al. [44] in pigs. Antimicrobial activities of lactic acid bacteria has also been reported against *Pseudomonas aeruginosa, Providencia vermicola, Alcaligenes faecalis* and MRSA in co culture [45].

use in the food industry [30], class II bacteriocins are relatively small, heat-stable and contain peptides while Class III bacteriocins are heat stable and also have a relatively large molecular weight [27]. The classes of bacteriocins produced by Gram-positive beneficial bacteria include lantibiotics and non-lantibiotic heat stable proteins [31] while Gram-negative bacteria pro-

Prebiotics are non-digestible food products that increase the relative abundance of beneficial microorganisms in the gut when ingested. Similar to the influence of complex plant polysaccharides on the gut microbiota composition and beneficial metabolite production, prebiotics enhance the production of short chain fatty acids such as butyrate—a metabolite that serves as an energy source for colonic epithelium. Examples of prebiotics used include inulin, fructooligosaccharides, and galactooligosaccharides, Some of these prebiotics are found naturally in foods (such as barley, wheat), and in garlic and raw onions. These prebiotics have been applied in malnourished Thai children and children from certain countries in Africa [33], South America and Europe in order to improve the adsorption of calcium as well as improve-

Synbiotics is a term used for the combined use of probiotics and prebiotics to achieve a more efficient impact on the gut microbiota [34]. This concept surfaced in order to tackle possible difficulty of the probiotics to establish itself in the gut. In this case, prebiotics and probiotics are co-administered in order to improve the growth/relative abundance and establishment of probiotics in the gastrointestinal tract of its host. The probiotic strains used in conjunction with prebiotics include Lactobacilli and Bifidobacilli, while the prebiotics used along with probiotic strains include inulin, galactooligosaccharide, and fructooligosaccharide. The combination of probiotics and prebiotics in therapy helps to give stability to the gut microbiota, which translates to overall health of the host's gut and the host in general. This combination also helps to enhance antimicrobial activity, and the combined effect includes; competition with the pathogen for adherence sites, production of metabolites that are toxic to the pathogens, production of compounds that degrade toxins produced by the pathogens, obstruction of attachment sites and toxin receptors, and modulation of the immune system to respond

**4. Antimicrobial potentials of beneficial microbes against antibiotic** 

The antimicrobial activities of beneficial microorganisms particularly lactic acid bacteria isolated from various sources against pathogens have been reported by many authors [7, 36].

duce colicin and microcin [32].

118 Antimicrobial Resistance - A Global Threat

*2.6.4. Prebiotics*

ment of growth [34].

effectively to pathogen invasion [35].

**resistant strains**

**3. Synbiotics**

The increasing emergence of antibiotic resistant uropathogens, yeast infection and recurrent infection has necessitated special interest in the antibacterial activity of lactic acid bacteria against uropathogens [46]. There are increasing scientific evidences that LAB can prevent the growth and attachment of pathogens to epithelial cells [47]. It was reported by Adeniyi et al. [48] that lactic acid bacteria isolated from various Nigerian based fermented foods exhibited varying antimicrobial activity against organisms implicated in urinary tract infections. *Weissella* spp. isolated from African fermented food and cow intestine demonstrated significant inhibitory activity against multi drug resistant uropathogens [7]. Lactic acid bacteria isolated from a menstruating Nigerian woman was shown to have antimicrobial activity against an array of uropathogens; *Escherichia coli, Proteus mirabilis* 42P, *Pseudomonas aeruginosa*, *Citrobacter freundii* and *Enterobacter cloacae* [49]. The organic acid produced by lactic acid bacteria has been proven to be inhibitory to *Neisseria gonorrhoeae* [50]. The antibacterial activity of lactic acid bacteria isolated from selected Nigerian vegetables against *Pseudomonas aeruginosa, Escherichia coli, Proteus penneri,* and *Enterococcus faecalis* was published by Bamidele et al. [51]. *Lactobacillus* spp. have been reported to inhibit the growth of *Candida albicans* and prevent the relapse of yeast infection [52]. The metabolite of *Lactobacillus plantarum* strain N4 was discovered to possess antiviral activities against coronavirus causing gastroenteritis [53], certain lactic acid bacteria have been suggested to be effective in reducing the severity and duration of acute rotavirus gastroenteritis [54].
